textproduct: Quad Cities

KEY MESSAGES

- A large storm system will move through the Midwest early this week. Rainfall amounts of 1"+ are possible for some locations (50-80% chance over eastern Iowa) and gusty south-southeast winds are expected area-wide.

- Isolated severe storms with a low but non-zero brief tornado threat are possible during the daytime Tuesday, mainly south of U.S. Highway 30.

- Behind the system, cooler conditions are expected and spotty rain showers will be possible for the second half of the week.

SHORT TERM /THROUGH TUESDAY/

Issued at 145 PM CST Mon Nov 2 2026

Today through Tonight:

SPC mesoanalysis had a 998mb low positioned over northeast South Dakota as of early this afternoon. Low-level moisture advection downstream of the low across the Mid to Upper Mississippi Valley has resulted in widespread low clouds and areas of drizzle and patchy light rain locally this morning into the early afternoon. Increasing large-scale ascent on eastern flank of a large upper trough, combined with increasing low/mid tropospheric warm air advection will lead to an increase in shower coverage later this afternoon/evening mainly across the western outlook area (west and northwest of the Quad Cities). This activity will be slow to make eastward progress as the aforementioned surface low shifts into northern Minnesota and a new area of low pressure begins to develop over eastern Kansas late tonight into Tuesday. Gusty south-southeast to south winds will continue through this period, reaching 30+ mph at times.

With an elongated surface trough axis set to hold west of eastern Iowa and northwest Illinois through much of Tuesday, our area will stay in the "warm and moist" sector of this storm system. Surface dewpoints will be very high for early November, peaking into the lower to possibly mid 60s, which will lead to a slightly unstable airmass and the potential for isolated thunderstorms (MUCAPE peaking <500 J/kg per HREF). A few of the storms could be strong to severe across roughly the southwest third of the outlook area on Tuesday (west and southwest of the Quad Cities). Exact timing is uncertain with the low potential encompassing both the morning and afternoon to evening hours. Typical for a high shear and low CAPE setup, the primary risks from the strongest storms are isolated damaging winds and a few brief spin up tornadoes.

Anomalously high PWATs (near 1.5-1.7") will support efficient rain producing showers/storms which could lead to the hardest hit areas receiving 1-2" of rainfall by Tuesday night. The highest amounts, and greatest probabilities for 1"+, are most favored across the west and northwest section of the outlook area.

LONG TERM /TUESDAY NIGHT THROUGH MONDAY/

Issued at 145 PM CST Mon Nov 2 2026

The active pattern will continue Tuesday night through Wednesday as a secondary surface low that's progged to develop over southwestern Kansas will sweep through the area late Tuesday, along with a surface cold front. Accumulating rainfall appears to wane in the wake of the fropa, but we will remain under a cloudy and cool pattern for the latter half of the week as a closed upper low is progged to develop over the Midwest. Confidence in this occurring is quite high, given the general consensus among the LREF ensemble cluster analysis. So, we will be dealing with persistent cyclonic flow, some lingering spotty light rain showers and some breezy winds, this time from the southwest. High temperatures on Thursday and Friday will cool down quite a bit compared to early this week but will still remain above average for early November - in the upper 50s to lower 60s.

Friday through the upcoming weekend: conditions look to become dry, along with some peaks of sunshine here and there. This is thanks to an area of high pressure that is progged to build over the region behind the departing cut-off low. High temperatures look to continue to warm into the upper 50s to near 60.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 552 PM CST Mon Nov 2 2026

Primarily IFR to MVFR conditions are expected through the TAF period. A storm system is slowly making its way through the region, with CIGs currently around 500-2000 ft across eastern Iowa and northwest Illinois. A line of showers with isolated thunderstorms is slowly progressing eastward early this evening, with showers ongoing as of 00Z at CID and expected at DBQ. Confidence in thunderstorms is highest at CID for this evening, and while storms are possible at DBQ mid-late evening into overnight, low confidence led to exclusion at this issuance.

Showers will become more widespread overnight with an increase in intensity as they near BRL and MLI towards 03/12Z. Some thunderstorms may be possible at BRL and MLI through the morning hours and have been included as a PROB30. Winds throughout the period will be southerly and breezy at 10-20 kts and gusts to 25-30 kts.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.